In the above-described technical field, Non Patent Literature 1 (NPL 1) discloses dividing a data set into two or more blocks and calculating statistical values for each of the blocks when performing statistical processing using the data set. NPL 1 further discloses a technology which, by reuse of a statistical value for each of the blocks calculated in advance, eliminates record scanning, accordingly reduces the Input/Output (I/O) amount and the calculation amount and consequently increases the speed of statistical processing of an attribute.